Friday, October 8, 2010

Swivelling foot mirror idea

8 Oct '10: I am sufficiently convinced by the performance of the mirrors in the last 3 weeks to take this further.
I told the guys on the N-tron forum that I would probably fit foot mirrors next Spring equinox to bounce summer light upwards. I have access to cheap metals, so if an idea is possible, cost is not an issue about trying it out. Once an idea takes hold it is difficult to postpone it, and during a lecture, I started doing sketches for a swivelling foot mirror that could be workable for winter and summer. Once the sketch is done, the details of swivelling and control begin to crystallise. So why not do it in Winter? That is the time when I am seeking gains, even if only marginal gains. With my collectors arrayed horizontally, heat and foot mirrors will help, side mirrors will do nothing useful.

The Top mirrors are not adjustable, because I didn't think I could make an adjusting mechanism that wouldn't rattle on windy nights or require more drilling of holes in the wall. So they are at a fixed angle of 60º, optimised for Winter sun. They are not useless in summer as the sun is only at 60º at midday, and there are times either side of midday when the sun will be lower and will bounce downward.

The Foot mirrors would be best to be sloping about 10º forward in summer, so the 60º midday sun bounces back up onto the front glass. For winter it needs to tilt further forward to bounce heat upwards to the centre height (but not too high, to avoid reflection off the front glass). As the range from winter to summer is 46º, I suppose that the mirror angle should vary by 23º from one season to the other = 10º, 20º and 30º.
Tilting the mirrors slightly back would be better on cloudy days to improve the daylight into the two bedroom windows below. I have shown the mirrors above as being TWO louvres, with a hinged control mechanism below, but this is a lot of work to make in detail.
Next, I need to make a 3D model to test out the idea, and forecast sizes and swivelling modes.

March 2015: Work on the solar dehydrator has been progressing well, and it is nearly complete, lacking merely the top surface of the sola...

Peveril Solar House

Welcome to Charging the Earth!

PEVERIL SOLAR is the first house in the UK to be entirely solar heated all year round! It is Carbon Net-Zero. It is an 'Active House' balancing inputs and outputs. PV generation and heating system consumption are in favourable balance using concepts of energy storage. Others claiming houses to be the first date from 2013 (and are unbuilt); this house exists and was carbon zero since 2011.

The name 'Charging' refers to 'storing energy underground': we have custom-built solar collectors, Surya Sunboxes, with ETFE front surfaces, to pump solar heat deep down into the earth. The building's heat pump gets all of this back in Realtime (immediately), Diurnially (later during the evenings) or Interseasonally (in Winter, months after the Summer).

Thus, we are augmenting the heatpump by storing long term heat in the summer, and we are defrosting the ground in winter-spring conditions, supplying solar energy directly to the heat pump, through its ground loop.

The five-way pentangle of Grid, Borehole, Heat pump, PV roof and Sunboxes have made the house Carbon Zero (for metered consumption). It's working, and we will continue to record data, to maintain that efficiency, and write it up in this website through to next year and beyond.

During theAutumn of 2012, we built a small house extension that is ultra insulated, with a higher energy gain than it loses.

Note, that we still have a net import of power from the Grid, because we still need power for lighting, cooking and appliances. But for the building emissions (as opposed to lifestyle emissions), we have achieved a credit balance of the regulated quantities, as recorded by meters.

The web-log follows the project from this general idea in Aug. 2009 to a technology of Surya Sunboxes, which seem to be effective - reducing energy costs of the house. Some of the Tabs will help you to get background and theory. You can click below to 'Follow Blog' to get email notifications - or email me. Please add Comments to the blog entries. If you find items in the Glossary that need explaining better, please ask. Thankyou!

Publications

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Kingspan, for Varisol Tubes

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MG Renewables

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Ice Energy Heat Pumps

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Holscot, for ETFE panels, re-fronting the Sunbox

About the Author...

David Nicholson-Cole is a Lecturer in Architecture at the University of Nottingham, with 35 years experience of architectural teaching and practice, which has included special interests in construction, building information modelling, tall building design and renewable energy technologies.

Finally, thanks to my deceased aunt, Margaret Cringle (1915-2008) whose legacy paid for most of the cost of this project - as one who was always turning lights out to save electricity, she would be very pleased!